Cathode for use in electrolytic cells.



No. 655,344. Patented.Aug. 7, I900. J. HARGREAVES.

CATHODE FOR USE IN ELECTROLYTIC CELLS.

(Application filed Oct. 2, 1899.)

(No Model.)

NITED STATES PATENT Orricn.

JAMES IIARGREAVES, OF VVIDNES, ENGLAND.

CATHODE FOR USE IN ELECTROLYTIC CELLS.

SPECIFICATION forming part of Letters Patent No. 655,344, dated August 7, 1900.

Original application filed January 31, 1899, Serial No. 704,057. Divided and this application filed October 2, 1899. Qerial No. 7 NO specimens.) I

To aZZ whom it may concern:

Be it known that I, JAMES HARGREAVES, a subject of the Queen of Great Britain and Ireland, residing at Farnworth-in-IVidnes, in the county of Lancaster, England, have invented a new and useful Improved Cathode for Use in Electrolytic Cells, (in respect whereof I have applied for a patent in Great Britain, to bear date July 14, 1898, No. 15,502,) of which the following is a specification.

This invention relates to the manufacture of alkalies by electrolysis; and it consists in an improved construction of cathode for use in electrolytic cells whereby the efficiency of the process is increased and the purity of the product improved.

This application is a division of my original application, Serial No. 7 04,057, filed January 31, 1899.

In electrolytic cells as ordinarily employed in the decomposition of salts 'by the Hargreaves-Bird process the cathode is usually composed of woven wire or gauze and is arranged contiguous to a porous diaphragm. Owing to the unevenness of the surface of the cathode (resulting from the crossing of the wires) the exposed surface of the diaphragm is amply sufficient for what is required fora satisfactory working, while the surface of the cathode in contact with the diaphragm is deficient, the purity of the product being prejudicially affected. IVith a view to rendering the contact between the cathode and the diaphragm more perfect I subject the woven-wire cathode to a rolling process,with the effect that the prominent points, where the wires cross one another, are flattened, as shown at a in the accompanying drawing. By subjecting the fabric to a rolling or other flattening proc ess an increased metallic surface in contact with the diaphragm is secured, the area of the intervening spaces where the current is inactive being correspondingly reduced.

It is essential to the proper working of the process that some portion of the surface of the diaphragm be uncovered by or out of contact with the cathode in order that the gases, steam, and washing-water may reach the surface of the diaphragm; but with Woven-wire cathodes as at present employed this surface is in excess of requirements. By the employment of the improved cathode the surface in contact with the diaphragm is inand washing-Water is not unduly impeded. In consequence of the increased cathode-surface the resistance to the current is diminished and the electric osmose increased, the Grahamic osmose (which permits the passage of undecomposed electrolyte through the dia phragm)'being at the same time diminished. As a consequence of this reduction in the proportion of undecomposed electrolyte passing through the diaphragm into the cathode-space the purity of the product is raised.

That I claim as my invention, and desire to secure by Letters Patent, is-

In an electrolytic cell, the combination with a porous diaphragm of a woven-wire cathode having the prominent parts of its surface, where the wires cross one another, flattened, substantially as and for the purposes set forth.

JAMES HAR GREAVES. IVitnesses:

ANTHONY BUCK OREEKE, EDWARD INGHAM.

creased, but the passage of the gases, steam, 

